Profile truing template for grinding machines or the like



Jan. 21, 1941. 3,0, EKHQLM ETAL 2,229,280

PROFILE TRUING TEMPLATE FOR GRINDING mcnmms on was LIKE Filed Aug. 19, 1939 l N VEN TORS THEIR ATTO EY.

Patented Jan. 21, 1941 UNITED STATES PROFILE T'RUING TEMPLATE FOR GRINDING MACHINES OR THE LIKE fiarl Gustav Ekholm and Bengt Daniel Ossian Westerluncl, Lidkoping, Sweden, assignors to Lidktipings Mekaniska Verkstads Aktiebolag, Fabriksgatan, Lidkoping, Sweden, a. corporation of Sweden Application August 10, 1939, Serial No. 289,350 In Sweden August 13, 1938 1 Claim.

The present invention relates to profile truing templates for grinding machines or the like. The object of such templates is to guide a forming or truing tool in such a manner that the grinding wheel obtains a profile which during grinding gives the desired shape to the work pieces. When grinding objects of difierent types and sizes for instance drills, it often happens that they correspond with each other as to one or several parts of the profile but differ as to other parts of the profile. The template according to the invention consists of a main part arranged to be mounted on a grinding machine or the like, one edge of the main part forming part of the guiding profile of the template, and at the side of this part a notch is provided to receive one of a set of inserts which is held in position by a holding member disposed in the main part. The part of the profile, which is the same for the difierent types of work pieces, is formed on the main part, and the part, which differs in different types, is formed on the separate in- .serts. The invention affords a substantial reduction in the cost for templates.

5 The annexed drawing shows the invention applied when grinding drills. Fig. 1 shows schematically a grinding wheel of a grinding machine, a drill to be ground and a truing device provided with a template according to the invention. Fig. 2 shows in detail the composite template according to the invention.

In Fig. 1 the numeral I designates the grinding wheel of a grinding machine and 2 a drill to be ground by means of the grinding wheel.

During grinding, the work piece is either supported between centres or the like, or, as in centerless grinding machines, by a regulating wheel and a work rest. For shaping the grinding wheel a truing device is provided, which is preferably mounted on the same bed or slide as the grinding wheel. The truing device consists of a guide 3 extending parallel with the shaft of the grinding wheel and a head 4 slidably arranged on the guide 3 and carrying a slide 5 which is slidable in a direction perpendicular to the guide 3 and supports a rod 6 with a diamond point 1 acting as the truing tool proper.

The rod 6 is carried by thread-engagement and is adjustable lengthwise by turning in the one or the other direction. The slide 5 is acted upon by a spring (not shown) in the direction towards the grinding wheel, and on its underside it is provided with a feeling member 8 which bears against the template 9. The guiding profile of the template substantially corresponds with the desired profile of the drill.

The drill consists of a conical part II which is adapted to be held by a chuck and a cutting part l2 and a narrow part l3 connecting these two parts. The grinding operation relates to the conical part II and the cutting part 12, but not to the narrow part [3. Before the grinding operation the grinding wheel is formed by means of the truing device described above. The grinding wheel is given two conical work surfaces l4,

l5, intended for the grinding of the conical part I I respectively the cutting part I2.

Spiral drills for different bore diameters are as a rule made with uniform conical parts within certain ranges of diameters. In accordance with the principle of the invention, therefore, the guiding profile corresponding to the conical part is formed on the main part 16, and the profile corresponding to the cutting part of the drill is formed on a separate insert 11, to be mounted on the main part It. In the manufacture of a group of spiral drills, the diameters of which lie within certain ranges, the same main part It can be used in connection with a number of different separate inserts ll, which last mentioned pieces are generally easy to manufacture at low costs.

The construction of the composite template is shown in Fig. 2, in which also various insert profiles for difierent bore diameters are shown with dot and dash lines. The main part I 6 of the template is substantially rectangular and has two bolt holes I8 for fixing it to the grinding machine. The main part [6 is formed with a notch for the insert ll. One of the short edges IQ of the notch'forms an acute angle with the long edge 20, and in the other short edge there is a threaded hole through which a screw 21 extends for coaction with the insert for holding the insert fixed to the main part It.

The invention is not restricted to the embodiment shown in the drawing. The template according to the invention can be used not only in connection with usual grinding machines but also in connection with polishing or lapping machines and the like. Furthermore the template can be arranged on the truing device for the regulating wheels of a centerless grinding machine.

We claim:

In a template for guiding a tool, the combination of a main part arranged to be mounted on a machine one edge of the main part forming part of the guiding profile of the template, a notch in said edge, a replaceable insert fitting into the notch and forming part of the guiding profile of the template, and holding means for detachably holding the insert in the notch.

CARL GUSTAV EKHOLM. BENGT DANIEL OSSIAN WESTERLUND. 

